EEXI vs. CII Made Simple: The Easy 2025 Breakdown for Shipowners

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Two of the most important decarbonization rules in global shipping, EEXI and CII, are creating confusion across the industry. Many shipowners are unsure how the rules differ or what actions are required to stay compliant. This easy-to-follow guide explains both regulations clearly so you can understand what they mean, how they affect your operations, and what steps to take next. No jargon, just the essential facts.

Before diving into the technical details, here’s a quick overview of what EEXI and CII actually mean. These definitions will help you get a clear baseline before tackling compliance or strategy.

EEXI (Energy Efficiency Existing Ship Index)	CII (Carbon Intensity Indicator)
A technical measure that evaluates how energy efficient a ship’s design is based on its specifications. Applies to existing ships built before IMO design efficiency rules came into effect.	An operational measure that rates how carbon efficient a ship is based on its real-world emissions per cargo mile over the course of a year.
Focuses on design limitations, such as installed engine power, fuel type, and hull shape. One-time compliance check tied to a ship’s technical file.	Involves continuous annual reporting and performance ratings from A (best) to E (worst). Poor performance requires a corrective action plan.
Typically met by limiting engine power, upgrading propellers, or retrofitting energy-saving devices.	Influenced by operational decisions such as voyage speed, route planning, and cargo optimization.

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Why EEXI and CII Were Created

The maritime industry contributes nearly 3 percent of global greenhouse gas emissions, and regulators are pushing hard for cleaner operations. EEXI and CII were both introduced by the IMO to help decarbonize shipping in measurable, enforceable ways. But each targets a different part of the emissions equation, design versus performance. The table below explains what motivated each rule and how they fit into the bigger picture.

Why These Rules Exist
Regulation	Core Objective	Reason for Implementation
EEXI	Improve design-based energy efficiency of older ships	Ships built before efficiency rules were unregulated. EEXI helps bring legacy fleets in line with modern standards.
CII	Track and improve real-world carbon performance	Design alone isn’t enough. CII ensures ships operate efficiently across actual voyages, routes, and cargo loads.
Both	Support IMO's 2030 and 2050 decarbonization goals	The shipping sector must reduce GHG intensity by 40% by 2030 and move toward full decarbonization by 2050.
Note: Based on IMO MARPOL Annex VI updates and 2023–2025 regulatory guidance.

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How EEXI and CII Are Calculated

Understanding how EEXI and CII are calculated is essential for compliance and fleet planning. EEXI is a one-time design-based metric, while CII is calculated annually based on operational carbon output. If you're looking for an easy way to explore emissions profiles across different ship types, try our Maritime Decarbonization Calculator to test fuel options, voyage speeds, and emission reductions.

How These Metrics Are Calculated
Regulation	Main Formula or Input	What It Measures
EEXI	CO₂ emissions per ton-mile based on design speed, deadweight, installed power, and engine/fuel type	How energy-efficient a ship is *by design* — like a fuel economy rating for an existing vessel
CII	Annual CO₂ emissions ÷ total transport work (cargo x distance)	Real-world *carbon intensity* — how much CO₂ your ship emits per mile of cargo carried
Compliance Benchmark	EEXI must be below a required limit set by ship type and size	CII rating must stay at C or above to avoid mandatory improvement plans
Note: These calculations are based on IMO guidelines under MARPOL Annex VI and verified performance data.

Penalties and Business Impact

Failure to meet EEXI and CII standards isn’t just a regulatory issue, it affects your bottom line. From ship detention to lost charter value, the penalties can escalate quickly. Below, we break down the specific risks of non-compliance and the broader financial consequences across the maritime supply chain.

Wider Business Impact
Stakeholder	Impact	Example
Shipowner	Lower resale value and increased compliance costs	Older bulkers see resale value drop 10–15% if unrated or D/E rated
Charterer	Limited pool of compliant ships to choose from	Many 2025 contracts now require a C-rating or better
Investor / Bank	Higher lending scrutiny based on carbon risk	Poseidon Principles tie loan terms to emissions performance
Note: Based on verified 2025 industry ESG disclosures, charter standards, and financial ESG frameworks.

What You Can Do to Comply with Both

Meeting both EEXI and CII requirements takes more than a one-time adjustment. Below are actionable tactics that shipowners and operators are using to stay compliant, without breaking the bank.

What’s Changing in 2025 and Beyond

EEXI and CII aren’t standing still. Several regulatory updates and industry shifts are already shaping the next phase of compliance and the pressure is rising from all sides. Here’s what’s coming next, and how it might affect your operations.

Upcoming Regulatory & Market Changes
Change	Timeline	Impact
EU ETS Expansion to Shipping	Fully phased in by 2026	Carbon emissions from voyages to/from EU now incur €45–€100/tCO₂ costs
Stricter CII Thresholds	Starting Jan 2026	Annual CII performance grades will tighten; more vessels risk falling into D or E
Carbon Intensity Target (IMO)	30% cut by 2030	Global target applies across all ship classes; pressure to retrofit or optimize fleet
Green Corridors & Fuel Mandates	2025–2030	Certain routes (e.g. Singapore–Rotterdam) may soon require low- or zero-carbon fuels
CII Expansion to Smaller Vessels	Expected by 2026–2027	Regulations may soon apply to vessels under 5,000 GT, widening the compliance scope
Note: Based on verified 2025 IMO proposals, EU regulations, and port policy announcements.

Navigating EEXI and CII doesn’t have to be overwhelming. While the regulations are evolving, most shipowners already have tools at their disposal to stay ahead. By taking proactive steps now, like improving fuel efficiency, monitoring carbon intensity, and using data-driven voyage planning, you not only comply with the rules but also improve your competitiveness.

As 2025 brings tighter thresholds and carbon pricing mechanisms, understanding the cost-benefit landscape of compliance actions becomes even more critical. Here’s a quick reference table to help you make informed decisions:

Compliance Strategy Guide (2025+)
Compliance Action	Helps With	Estimated Cost	Operational Benefit
Engine Power Limitation (EPL)	EEXI	$10,000–$50,000 per vessel	Fastest path to EEXI compliance for existing tonnage
Hull Cleaning & Propeller Polishing	Both	$3,000–$10,000 per vessel (quarterly)	Improves fuel efficiency by up to 10%
Voyage Optimization Software	CII	$15,000–$50,000 per year	Real-time emissions tracking, weather routing, speed control
Biofuel or LNG Blending	Both	20–50% higher OPEX vs. conventional fuel	Reduces CO₂ intensity while meeting client ESG targets
Installing Shaft Power Limitation (ShaPoLi)	EEXI	$40,000–$80,000 per vessel	Alternative to full engine retrofit; simple compliance lever
Data Monitoring Systems (e.g. Noon Reports)	CII	$5,000–$20,000 per year	Enables corrective decisions mid-voyage to preserve CII score
Fleet-Wide ESG Strategy Alignment	Both	Varies — strategic initiative	Improves access to charter contracts and green financing
Note: Based on verified 2024–2025 industry compliance benchmarks and cost data.

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